textproduct: Rapid City

KEY MESSAGES

- A period of strong winds today as fast-moving cold front moves through - Arctic air arrives Thursday, intensifies Friday, and then moderates for the weekend into early next week

DISCUSSION

(Today Through Tuesday) Issued at 223 AM MST Wed Jan 21 2026

09z surface analysis had low over central MB and cold front into central MT with 6mb/3hr pressure rises behind it. Cold front driven by shortwave over AB/SK per water vapour, racing southeast on 120kt jet. MT/ND radar starting to show some returns near the Canadian border, but system is moisture-starved on the southwest side per nighttime microphysics RGB loop. Effect of this system the main short term forecast concern, and then arctic air intrusion for Thursday/Friday.

Today, shortwave barrels southeast driving cold front through the CWA this morning with 4-7mb/3hr pressure rises tapping into 40-60kt lowest mixed layer winds. Given cold air advection, good setup for high winds for the squeeze areas from K2WX-KRAP where there is a 60-90% chance of >60mph wind gusts with ECMWF EFI indicating 70-95th percentile wind gusts. Bufkit soundings support a 2-4 hour period of strong winds. Have hoisted High Wind Warning to account, surrounded by Wind Advisory. Moisture will be limited with system with best QG/frontogenetic forcing north/east of the area, but some light snow may occur from K2WX-KICR with minor accumulations. Looking at yesterday's snow/fog RGB, it suggests some blowing snow may occur north of I-90, so have mentioned in the wind highlights. Most folks will have high temperatures this morning with steady/falling temperatures this afternoon.

Tonight through Friday, upper low over Hudson Bay keeps northern plains under cyclonic flow with arctic gate opening per sustained low level cold air advection through Friday. ~1052mb high eventually ends up over the Dakotas. Wind chills Thursday/Friday morning will be very cold with the best chance for sub -25F wind chills Friday morning (LREF 40-70% chance from K2WX-KICR). Lack of snowcover in the southwest means somewhat less cold. Future forecasts will need to consider cold headlines for Thursday/Friday morning. Snow chances under cyclonic flow present with perhaps some arctic stratus/flurries. Not expecting anything significant.

Moderating temperatures begin over the weekend as warmer air erodes arctic air from west to east per decreasing influence of Hudson Bay low. Temperatures spreads 10-20F, but that isn't surprising given stubborn nature of arctic air in January. Haven't strayed far from guidance.

AVIATION

(For the 12Z TAFS Through 12Z Thursday Morning) Issued At 418 AM MST Wed Jan 21 2026

Northwest wind gusts from 35-55kts will occur today behind a strong cold front, strongest over northwestern SD, which includes the KRAP terminal. Winds will slowly subside late this afternoon/evening. Local MVFR/IFR conditions are expected over far northwestern SD due to snow this morning. Otherwise, VFR conditions will prevail.

UNR WATCHES/WARNINGS/ADVISORIES

SD...High Wind Warning until 5 PM MST this afternoon for SDZ001-002- 012-013-026-031-072-073-078. Wind Advisory until 5 PM MST /6 PM CST/ this afternoon for SDZ014-025-030-032-041>044-046-047-049-075>077. WY...None.